<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id="app">
        <input type="text" v-model="msg">
        <h2>{{msg}}</h2>
    </div>
</body>
<script src="./js/vue.js"></script>
<script>
    var vm = new Vue({
        el:"#app",
        data:{
            msg:"hello word"
        }
    })
</script>
</html>